Floatable partition for liquid storage tanks



Aug. 12, 1958 J. H. MQCLINTOCK ETAL I 2,847,142

FLOATABLE PARTITION FOR LIQUID STORAGE TANKS Filed July 8, 1954 3Sheets-Sheet 1 Rob t w Mam, Jr. lnventors y Attorney FLOATABLE PARTITIONFOR LI QUID STORAGE TANKS Filed July 8, 1954 3 Sheets-Sheet 2 John H.McClintock Rob t w Manz JR Inventors MW Attorney 1958 J. H. M CLINTOCKnu. 2,847,142

LIQUID STORAGE TANKS FLOATABLE PARTITION FOR Filed July 8, 1954 3Sheets-Sheet 3 .m 2 I: w 2 2 b- E |0| 9 W3 n I:

FIG-3 .w W I I Q 6 {3 G... F

Attorney United States Patent 2,847,142 'FLOATA'BLE PARTITION FOR LIQUIDSTORAGE TANKS John H. McClintock, Cranford, and Robert W. Martz, Jr.,opatcong, N. J., assignors to Esso Research and Engineering Company, acorporation of'Delaware Application July 8, 1954,;Serial No. 442,170 13Claims. (Cl. 220-26) produced by 2,847,142 Patented Aug. 12, 1958 Qihcetank as shown in Fig. 1, taken along the line Fig. 1; 1

gas into the vapor space above .spaced arcuately shaped angle ironreinforcing members Fig. 3 is an enlarged view in vertical section of aportion of and of an inflatable cover according between the cover andtank wall as indicated in Figs 1 and Fig. 4 is a view similar to that ofFig. 1, taken along the line IV-IV of Fig. 5, illustrating another formof and also for introducing inflation the cover;

ig. 5 is a view in horizontal section through a storage tank as shown inFig. 4, taken along the line V.V of Fig. 4;

such as designated in Fig. 3

cone shaped roof 13, including a hatchway or manhole 14 opening throughthe roof.

floor portion 22 is formed of three sheets disposedwith are cementedtogether, and the o as spaced relation to the tank axis x--x, and thecenter point of the partition, and at such distance from the axis as tobe substantially alignable vertically with reference to the roofhatchway 14. The hatch cover 25 is provided with spring hinges 25a, andmay be opened by means of a cable attachment 25b.

The annular pontoon element 21 has an outside di ameter somewhat smallerthan the internal diameter of the tank at the wall, and also less thanthat at the innermost edge of the angular reinforcing members 12. For

example, in a tank having an internal diameter of about feet 4 inchesand with reinforcing members extending horizontally from the wall intothe storage space for a distance of about 3 inches, the pontoon element21 might have an outside diameter of about 9 feet 2 inches. With suchdimensions the diameter of pontoon would be about 8 inches less thandiameter of the tank at the inner edge of the reinforcing members 12,and about 14 inches less than the diameter of the tank from wall towall. Thus when centered on the tank axis, the pontoon could be freelyand buoyantly supported on the uppper surface of the liquid contents ofthe tank so as to be reciprocally movable vertically in substantiallyright angular relation to the vertical axis of the tank.

To center the pontoon element in the tank and to provide a substantialyfluid-tight seal between the pontoon and tank walls, the outer peripheryof the pontoon carries annular sealing means 2.6 extended radiallyoutward therefrom into frictional contact with the tank walls. As shownin Figs. 1, 2 and 3 of the drawings, the centering and sealing means isa laminated means composed of a vertical series of annular elements eachformed of a flexible, deformable material similar to that of the pontoon21, and membrane 22. In the form shown the number of elements is odd,including a mid-element 27, and successive pairs of elements such asdesignated by the numerals 28a and 23b, and 29a and 2%, wherein themid-element has a radial dimension outwardly from the outer periphery ofthe pontoon which is greater than one-half the difference between theouter diameter of the pontoon and the inner diameter of the tank, and insucceeding pairs the radial dimension of each element is equal to thatof the other in that pair but less than that of the mid-element, andwherein from pair to pair the radial dimension of the elementsdiminishes from pair to pair. In Fig. 3 the paired elements and theirrelationships to each other and to the mid-element are clearly shown,with one element of each pair disposed above and one below themid-element in the series. Further, although all the elements 27, 2&1,28b, 29a and 2% are each shown as of a single thickness substantiallyequal to that of the pontoon and membrane material, these individualelements may be made thinner or thicker as desired and individually alsomay be laminated. The primary requirement in any event is that theyprovide a flexible sealing means between the pontoon 21 and tank wall 1which means is deformable as required to ride over any protruding partof the wall surface, such as angles 12, and yet to provide adequateresistance to hori zontal displacement of the floating partition such asto maintain the partition substantially centered on the vertical axis ofthe tank. Also, although the sealing means may be made to besubstantially self-supporting by suitable selection and gradation of thethickness of the laminae, principally the paired elements, it ispreferred that they be provided with supplementary annular stiffeningmeans such as the elements 3t and 31. These elements are preferably of asubstantially rigid material such as metal or hard rubber, plastic, orother similar materials with or without integral metal reinforcement.Any suitable means may be employed to secure the elements 30 and 31 tothe outer surface of the pontoon, or, as shown, to the surface of thesealing means as attached to the pontoon. Further, in the assembledsealing means shown, the surfaces of the several laminae are cementedtogether at their inner edges within the outer periphery of the elements31 and 31, and also to the inner opposed surfaces of these elements, andmay be further secured as by means of rivets 31c extending through theelements 30 and 31 as shown. Beyond .the outer edge of the elements 30and 31, the elements 27, 28a, 23b, 29a, and 2% are in free surfacecontact. Alternately, however, these elements may be cemented togetherfrom their roots at the pontoon outer periphery to their outer edges.The annular elements 27, 2%, 23b, 29a, 29b, 39, and 31 may also consistof a plurality of arcuate sections arranged in either overlapping orbutt joint relation with the joints of one element in circumferentiallystaggered relation to those of another.

In addition to the peripheral sealing means and floor closure, escribedabove, the pontoon element as shown is provided with means for inflatingand deflating the pontoon, and also supplementary means for retainingthe assembly against rotational movement within the tank. In thedrawings, the inflation and deflation means is a valve 32, such as atire valve, opening through the material of the pontoon. As laterdescribed this means may include semi-permanent conduit connections nalsource of fluid under pressure, or may include a pressurized fluidcontainer mounted on the pontoon. Also, where desired, the pontoon maybe divided internally into a series of fluid-tight compartments withindividual valve means for each compartmel t Various retainer means mayalso be provided. A simple form is illustrated, consisting of a pair ofguy ropes 35 attached to the pontoon surface at opposite ends of achordal dimen sion which is less than the diameter of the pontoon at thelevel of attachment. Where the change in level of the liquid contents isinfrequent, the guy ropes may be belayed on any suitable cleat withinthe hatchway 14; otherwise a spring actuated tension reel may beemployed.

An alternate form of the invention is illustrated in Figs. 4, 5 and 6.In these figures corresponding parts are designated by numeralscorresponding to those employed in the description of Figs. 1, 2 and 3.Thus, the numeral 111 designates a tank, 112 angular, annularreinforcing members, 113 a tank roof, and 114 a hatchway. The numeral115 designates a body of liquid in the tank with a vapor space 116 aboveit. The numeral 121 designates a pontoon member which differs from thatshown in Figs. 1, 2 and 3, in being provided with a series of radialspoke elements such as 121a, 121b, and 1210. These elements are hollowtubular members communieating at their outer ends with the main pontoonmember 121. Preferably the inner or hub ends of the spoke elements aresealed one from another, and the pontoon member divided into threecompartments by means of fluid-tight partitions, indicated by dottedlines in Fig. 5, and designated by the numeral 121d, disposed internallyand transversely of the tubular pontoon, intermediate the communicatingattachment of the spokes with the pontoon. The enclosed area of theannular pontoon 121 is closed by means of a membrane closure or floorportion 122 attached to the pontoon 121 substantially as is the membrane22 to pontoon 21 of Figs. 1, 2 and 3. The membrane 122 may also beattached to the spoke elements in a similar fashion. A hatchway 124 andbatch cover 125 with spring hinges 125a and cable attachment 12% allcorrespond to their previously described counterparts 24, 25, 25a and25b, and are similarly located with reference to the vertical axis xt,of the tank 111 in Figs. 4, 5 and 6.

In the apparatus illustrated by the latter figures, the annular sealingand centering means is provided by a vertical series of annular finelements, 127, 128:: and 128b, each secured at its inner periphery tothe outer periphery of the pontoon 121 similarly to the elements 27, 28aand 28b previously described. In the form now contemplated, the elements127, 128a and 12812 are vertically spaced, and each element extendsradially outward to an exterfrom the pontoon into frictional,

theinner wall.

interior of the spoke elements 'height of the tank.

' Most desirably 'the assembly .slidable contact with referably thespacing of vtheilayered elements is such as'to'permit at least twoelements, toremain in sealing contact with the wall of the tank while athird element may be deformed by passage over an obstruction orprojection thereon. n Fig. 6, the element 127 is shown to be.deformed bythe angle reinforcement member 112, while the elements 128a and W128])are in sealing contact with the tank wall. Also as .illustrated, theindividualelements 127, .128aand '128b are thickerthan the previouslydescribed elements 27, 23a andf28b, 'soas tobesubstantiallyself-supporting. The

' elements127, 128a and 12812, howevenalso may be pro- In the preferredform of the apparatus referred to, wherein the spoke elements are sealedone from another, separate means for inflating the pontoon compartmentsare provided. In Figs. 4, 5 and 6 such means include three valveelements 132a, 132b, and 1320 open into the 121a, 1211: and 1210, reareconnected to a comflexible conduit 134 conspectively. All of thesevalves end of a rigid conduit 135 supported on thetank roof and wall.The other end of the conduit 135 is connected to a suitable source (notshown) of a gaseous material under pressure. 'The flexibleconduitprovided is of a length substantially equal to the If desired,the'flexible conduit may bemounted .on an automatic, springoperatedtake-up age from the pontoon may be readily discovered fromAnotherfeature of the form of floatable partition, as illustrated inFigs. 4, 5 and 6 resides in-theprovision of means for discharging the,gas used to inflate the pontoon member into the vapor space of the tank.Such means is afforded by a plurality of pressure relief valvesand"111'by,insertion through an opening or hatchway such as designatedby the numerals 14 and 114. Where conduit means such .as 134 and 135 ofFigs. 4, 5 and 6 are to be used, in folding the assembly the valves132a,

132b, andl32c are preferably left exposed so thatthe flexible conduithand. Likewise 134 may be connected thereto beforein folding or rollingthe assembly as illustrated in ,Figsl, 2 and 3, it is desirable that the:valve '32 be available for connection with a detachable pressureconduit means. ,Of course if the pontoon is provided wi'th automaticself-containedinflation means,

no special-rolling or folding technique need be employed. will beintroduced into the tank at a time when the liquid surface is at .anintermeof ;said pontoon 'terial secured at its diate level in the tank,and preferably when the .tank is atileast half'full, in, ordertofacilitatemanipulation during or after insertion.

After inserting the assembly through the hatchwayor opening in the tankthe foldsmay be shakensout and while held as by the restraining ropes orcables 33 or 133, the pontoon member is at least partially inflated. Theassembly may then be dropped onto the liquid surface and its positionadjusted so as to bring the 'hatcht 24 or 124 into alignment with thehatch 14 or 114 as illustrated and described,fbefore complete inflationof-the pontoon member forces the sealing meansinto complete pressurecontact With the tank Walls. .When'in position, the inflation ofthepontoon member is completed and the assembly is then in service.

in fabricating therassembly, the displacement thereof is gauged so thatthe membrane closure element or floor portion 22 or 122 is assured ofintimate'surface contact With-the liquid over substantially its entirearea. displacementis also gauged so that. displaced liquid will levelhigh enough to make contact with the sealing means under any normaloperating condition.

'terial, an annular seal ring ofsa flexible, deformable material securedat its inner periphery to the outer periphery element, .in fluid-tightrelation thereto and extending radially outward therefrom, asubstantially hollow, a substantially fluid-impervious, flexible,deformable material, an annular seal ring of a'flexible, deformablemainner periphery to the outer periphradially outward therefrom,said..annular seal ring including a plurality of individual, annularelements disposed in. parallel, superposed relation, of which eachelement is secured at its inner periphery to the outer peripheralsurface of said pontoonelement, asub- 'stantially flat membrance of aflexible, deformable-material joined to the outer surface of saidpontoon. element in substantially fluid-tight, tangential relation.thereto, and forming a floor for said pontoon extending overr-theentirearea enclosed thereby, and valve means communieating Withtheinterior of said pontoon element adapted to permit inflation anddeflation of said pontoon element.

3. A collapsible floating roof assembly comprising a tubular, annular,continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable materialsecured in its inner periphery tothe outer periphcryof said pontoon element, in fluid-tight relation therements increasingin equal pairs inwardly from the pair of elements forming the upper andlower surfaces of said seal ring, and wherein said odd member of saidelements is the middle member and has an outer diameter greater than anyother member, a substantially flat membrane of a flexible, deformablematerial joined to the outer surface of said pontoon element insubstantially fluidtight, tangential relation thereto, and forming afloor for said pontoon extending over the entire area enclosed thereby,and valve means communicating with the interior of said pontoon elementadapted to permit inflation of said pontoon element.

4. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured in its inner periphery to the outerperiphery of said pontoon element in fluid-tight relation thereto andextended radially outward therefrom, said annular seal ring including aplurality of individual, annular elements disposed in parallel,superposed relation, of which each element is secured at its innerperiphery to the outer peripheral surface of said pontoon element, apair of annular support elements secured at their inner peripheries tothe outer periphery of said pontoon element, the elements of said pairbeing disposed respectively above and below said annular seal ring insurface contact therewith, said support elements having an outerdiameter smaller than that of any of said individual, annular seal ringelements, a substantially flat membrane of a flexible, deformablematerial joined to the outer surface of said pontoon element insubstantially fluid-tight, tangential relation thereto, and forming afloor for said pontoon extending over the entire area thereby, and valvemeans communicating with the interior of said pontoon element adapted topermit inflation and deflation of said pontoon element.

5. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured at its inner periphery to the outerperiphery of said pontoon element in fluid-tight relation thereto andextended radially outward therefrom, said annular seal ring including anular elements disposed in parallel, superposed relation, of which eachelement is secured at its inner periphery to the outer peripheralsurface of said pontoon element, a pair of annular semi-rigid supportelements of a heavy gauge material similar to that of said annular sealring secured at their inner peripheries to the outer peripheral surfaceof said pontoon, the elements of said pair being disposed respectivelyabove and below said annular seal ring in surface contact therewith,said supportelements having an outer diameter smaller than that of anysaid individual, annular seal ring elements, a substantially flatmembrane of a flexible, deformable material joined to the outer surfaceof said pontoon element in substantially fluid-tight, tangentialrelation thereto, and forming a floor for said pontoon extending overthe entire area enclosed thereby, and valve means communicating with theinterior of said pontoon element adapted to permit inflation anddeflection of said pontoon element.

6. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured at its inner periphery to the outerperiphery of said pontoon element, in fluid-tight relation thereto andextending radially outward therefrom, a flat membrane of a flexible,deformable material joined to the outer surface of said pontoon elementin substantially fluid-tight tangential relation thereto, and forming afloor for said pontoon extending over the entire area enclosed thereby,valve means communicating with plurality of individual, an-

substantially Y the interior of said pontoon element adapted to permitinflation and deflation of said pontoon element, a series of hollow,tubular, spoke-like flotation elements, formed of said substantiallyfluid-impervious, flexible, deformable material, disposed radially withrelation to said pontoon element, each of said spoke-like flotationelements secured at its outer end to the inner peripheral surface ofsaid pontoon element and in substantially open communication therewith.

7. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured at its inner periphery to the outerperiphery of said pontoon element, in fluid-tight relation thereto andextending radially outward therefrom, a substantially flat membrane of aflexible, deformable material joined to the outer surface of saidpontoon element in substantially fluid-tight tangential relationthereto, and forming a floor for said pontoon extending over the entirearea enclosed thereby, valve means communicating with the interior ofsaid pontoon element adapted to permit inflation and deflation of saidpontoon element, a series of hollow, tubular, spoke-like flotationelements formed of said substantially fluid-impervious, flexible,deformable material, disposed radially with relation to said pontoonelement, each of said spoke-like flotation elements secured at its outerend to the inner peripheral surface of said pontoon element, insubstantially open communication therewith, and in substantiallytangential surface contact with said membrane.

8. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured at its inner periphery to the outerperiphery of said pontoon element, in fluid-tight relation thereto andextending radially outward therefrom, a substantially flat membrane of aflexible, deformable material joined to the outer surface of saidpontoon element in substantially fluid-tight tangential relationthereto, and forming a floor for said pontoon extending over the entirearea enclosed thereby, a series of hollow, tubular, spoke-like flotationelements, formed of said substantially fluid-impervious, flexible,deformable material, dis posed radially with relation to said pontoonelement, each of said spoke-like flotation elements secured at its outerend to the inner peripheral surface of said pontoon elements insubstantially open communication therewith, a

series of vertical partitions each disposed internally of said pontoonelement in fluid-tight relation thereto intermediate the outer ends ofan adjacent pair of said flotation elements, said flotation elementseach having a sealed junction with said other flotation elements attheir inner ends and an individual valve means opening through the wallof each flotation element into communication with the interior of saidpontoon element through said flotation element.

9. A collapsible floating roof assembly comprising a hollow, tubular,annular, continuous pontoon element of a substantially fluid-impervious,flexible, deformable material, an annular seal ring of a flexible,deformable material secured in its inner periphery to the outerperiphery of said pontoon element in fluid-tight relation thereto andextended radially outward therefrom, said annular seal ring including avertical series of individual annular elements disposed in verticallyspaced parallel relation peripherally of said continuous pontoon elementeach of said annular elements being attached at its inner edge influid-tight relation to said pontoon element, a substantially flatmembrane of a flexible, deformable material joined to the outer surfaceof said pontoon element in substantially fluid-tight tangential relationthereto, and forming a floor for said pontoon extending over the entirearea enclosed thereby, and valve means com- 10. I -.a rigidroofsupported on said municating with the .intei'ior pf said pontoon:element adapted. to penniti inflation and deflation. of. said pontoonelement.

n a storagetank havingsubstantially verticalwalls,

substantially fluid-impervious,.lfiexible, deformable material having.an outer. diameter. less than. the. innerdiamof a substantiallyfluid-impervious .fiexible defonnable ismaterial joined'in fl'uid-tightrelation-Jo the=uter surface of said pontoon element sosasnto center ofsaid area and the outer ends extending outward to a ing .a hollow,

ment of a substantially fluid-impervious, flexible, .de-

formable material having .an .outer diameter less than in said liquidwhen an annular seal ring of a flexible, deformable material having aninner diameter substantially equal to the outer diameter of said pontoonelement attached at its inner periphery in fluid-tight relation to theouter periphery of said pontoon element, said ring extending radiallyoutward from said pontoon element into frictional, pressure engagementwith the inner wall of said tank, said ring having an outer diameterslightly greater than the inner diameter of said tank, a substantiallyflat membrane of a substantially fluid-impervious, flexible, deformablematerial joined in fluid-tight relation to the outer surface of saidpontoon element so as to extend over the entire area enclosed by saidpontoon element and forming a floor adapted to be disposed in intimatesurface contact with the body of liquid contained by said tank, a seriesof vertical partitions internally of said pontoon element disposed influid-tight relation thereto and at regular spaced intervals therein todivide the interior thereof into a series of separate compartments ofsubstantially equal volume, a plurality of hollow, tubular flotationelements, each formed of said substantially fluid-impervious, flexible,deformable material and equal in number to the number of saidcompartments, each of said flotation elements having an inner and anouter end and disposed radially of the area enclosed by said pontoonelement with the inner ends of said flotation elements joined influid-tight, non-communicating relation substantially at the center ofsaid area and the outer ends extending outward to a fluid-tight juncturewith the inner peripheral surface of said pontoon element, saidflotation elements each communicating at itsouter end with a separatecompartment of said series of compartments, individual valve meansopening into the interior of each said flotadisposed Within said tankconnected at one end in fluidtight communication With the inner end ofsaid rigid conduit and at the other end extended into fluid-tightcommunication with each of said valves opening into the interiors ofsaid flotation elements, pressure relief valve means opening from eachof said series of separate compartments in means connected in said rigidconduit adapted to said pontoon element, and control valve regulatefluid flow through said rigid and flexible conduits, and pressure insaid pontoon element.

References Cited in the file of this patent UNITED STATES PATENTS GreatBritain June 24, 1938

